As for pixels of active matrix display devices using light-emitting elements, a variety of circuit configurations are proposed. In general, a pixel is provided with at least a light-emitting element, a transistor which controls input of a data signal to the pixel, and a transistor which controls a current supplied to the light-emitting element (driving transistor). Supplying a drain current flowing in the driving transistor to the light-emitting element makes the light-emitting element emit light at a luminance corresponding to the drain current value. The drain current of the driving transistor is controlled by the voltage of a data signal.
Therefore, when there is a variation in the electrical characteristics (such as the threshold voltage and the field-effect mobility) of the driving transistor between a plurality of pixels included in a screen of a display device, a variation in the luminance of the light-emitting element is caused even when data signals with the same voltage are supplied to these pixels. The variation in the electrical characteristics of the driving transistor between a plurality of pixels is a cause of a reduction in the display quality of the display device.
Meanwhile, an increase in the number of pixels in an active matrix display device is advanced to achieve high resolution, and as many as hundreds of thousands to tens of millions of pixels are provided in one display device. For example, in the case of a resolution of full-HD, the number of pixels is 1366×768×3 (RGB)=1,049,088; and in the case of 8K4K (Super Hi-Vision), it is 7,680×4,320×3 (RGB)=33,177,600. It is extremely difficult to completely match the electrical characteristics of driving transistors in a large number of pixels. Thus, obtaining electrical characteristics of the driving transistor and correcting the luminance of the light-emitting element are proposed (e.g., see Patent Document 1).
To meet demand for multiple gray levels, higher definition, and the like of a display portion, a dedicated IC (a driver IC) is used as a driver circuit of a display device, particularly as a source driver circuit for generating a data signal from an image signal (e.g., see Patent Document 2).